Fastener driving tool

ABSTRACT

A stapler or nailer for applying such fasteners to inaccessible workpiece locations includes a &#39;&#39;&#39;&#39;long nose&#39;&#39;&#39;&#39; or extended nosepiece structure forming a drive track. Although the drive track is greatly elongated compared to a conventional tool, a fastener driving blade and a coupled piston-cylinder motor do not require corresponding longer operating strokes because the fastener is advanced through the drive track in steps on successive driver blade strokes of conventional length. This incremental movement is obtained by using a stepped driver blade to move, on successive strokes of the driver blade, a fastener supplied from a magazine through one or more fastener storage or retaining stations spaced along the drive track to a discharge opening at the lower end of the drive track.

United States Patent [191 Obergfell v v[451 Sept. 10, 1974 FASTENERDRIVING TOOL Allen R. Obergfell, Park Ridge, 111.

[73] Assignee: Fastener Corporation, Franklin Park, Ill.

[22 Filed: Jan. 26, 1973 21 Appl. No.: 327,105

[75] Inventor:

[52] US. Cl 227/120, 227/109, 227/138 [51] Int. Cl. B25c 1/04 [58] Fieldof Search 227/82, 85, 86, 93, 97, 227/98, 107, 109, 110, 119-130,134-139, 142, 149

[56] References Cited UNITED STATES PATENTS 582,103 5/1897 Smith 227/120X 2,829,369 4/1958 Browning 227/113 2,927,324 3/1960 Ollig et al.227/118 3,168,745 2/1965 Winters 227/99 X 3,190,522 6/1965 Wintersm,227/40 3,249,280 5/1966 Cabot et a]. 227/138 X PrimaryExaminer-Granville Y. Custer, Jr. Attorney, Agent, or Firm-Mason,Kolehmainen, Rathburn & Wyss I [57] ABSTRACT A stapler or nailer forapplying such fasteners to inaccessible workpiece locations includes along nose or extended nosepiece structure forming a drive track.Although the drive track is greatly elongated compared to a conventionaltool, a fastener driving blade and a coupled piston-cylinder motor donot require corresponding longer operating strokes because the fasteneris advanced through the drive track in steps on successive driver bladestrokes of conventional length. This incremental movement is obtained byusing a stepped driver bladeto move, on successive strokes of the driverblade, a fastener supplied from a magazine through one or more fastenerstorage or retaining stations spaced along the drive track to adischarge opening at the lower end of the drive track.

FASTENER DRIVING TOOL The present invention relates to a fastenerapplying tool and, more particularly, to such a tool which requires onlya normal operating stroke while providing a substantially elongatednosepiece.

Fastener applying or driving tools such as pneumatically actuatedstaplers and nailers are frequently used in applications in which itisnecessary to provide a large clearance between the end of thenosepiece structure from which the nail or staple is driven into aworkpiece and the remainder of the tool housing. ln most tools, themagazine assembly extending rearwardly from the point on the nosepieceat which the fasteners are fed into the drive track provides thestructure that limits the clearance. Since the lower end of the fastenerdriver is usually disposed just above the fastener at the point in thedrive track at which the fastener is supplied by the magazine assembly,any increase in the length of the clearance between the workpieceengaging end of the nosepiece and the magazine must be accompanied by anincrease in the stroke of the driver and its connected piston.

As an example, U.S. Pat. No. 3,190,522 discloses a group of pneumaticstapling tools for fastening coil springs to a frame in which the sizeof the coil springs necessitates a large clearance between the staplemagazine and the workpiece engaging end of the nosepiece. This clearanceis supplied by providing a long nose on the tool with an increase in thelength of the cylinder and the piston-driver blade stroke. Thisincreased tool size results in stationary assembly fixtures that arelarger than desirable and in tools that are unwieldy to operatemanually. The necessity of increasing the cylinder length to provide theincreased stroke required by the long nose tool also means that longnose tools must be specially designed and that the standard pneumaticmotor drive systems for the large volume hand tools cannot be used inlong nose applications.

Accordingly, one object of the present invention is to provide a new andimproved fastener applying tool.

Another object is to provide a fastener driving tool with a nosepiece ordrive track of substantially increased length that does not require anincreased stroke for the driver operating means.

A further object is to provide a long nose fastener driving tool capableof being operated by pneumatic motors used in conventional tools.

A further object is to provide a fastener driving tool in which afastener, such as a staple or nail, is advanced through a drive track inincrements by a series of strokes of an operating means.

A further object is to provide a fastener driving tool including one ormore fastener storage or retaining stations spaced along a drive track.

Another object of the present invention is to provide a fastenerapplying tool for driving a fastener through a drive track in aplurality of strokes in which the drive track and a fastener drivermovable therein have sections of different widths or thicknesses.

A further object is to provide a fastener applying tool with a drivetrack having fastener storage assemblies for storing fasteners in thedrive track wherein the storage assemblies include means for retaining afastener against retrogressive movement and for transferring thefastener to different sections of the drive track.

ln accordance with these and many other objects, an embodiment of thepresent invention comprises a pneumatically actuated fastener driving orapplying tool having a substantially elongated nosepiece structureaffording a substantial clearance between the fastener dischargingopening in the lower end of the nosepiece and the remainder of the toolhousing so as to afford a tool capable of reaching inaccessibleworkpiece locations. This is accomplished without increasing the lengthof the operating stroke of thefastener blade slidably mounted in thedrive track and its connected pneumatic piston by provding one or anumber of fastener storing or retaining stations spaced along the lengthof the drive track. The fastener driving blade is provided with a seriesof corresponding stepped fastener engaging portions, the upper one ofwhich is disposed adjacent the point at which fasteners are supplied tothe drive track from a magazine and the remainder of which are disposedadjacent successive fastener storing stations.

Accordingly, when the tool is first operated following the provision ofa supply of fasteners in the magazine, the first fastener such as astaple is transferred from its point of introduction into the drivetrack to the first storing station by the related portion of the driverblade, and no fastener is applied to the workpiece. The firsttransferred fastener is retained in the storage station as the driverblade is retracted to its normal position. When the driver blade isretracted, the storage station transfers the fastener beneath the nextstep on the driver blade. Accordingly, when the tool is next operated,the staple in the storage station is either driven into the workpiece ortransferred to a subsequent storage station, while the uppermost step onthe driver blade transfers a fastener or staple from the drive trackinlet to the first storage station to replace the staple previouslystored therein and now being transferred by another section of thedriver blade.

In this manner, by providing one or more storage stations andcorresponding staple engaging portions on the driver blade, the staplesor fasteners can be successively transferred along the length of thedrive track and driven into a workpiece during a series of cycles ofoperation of the tool, all using a pneumatic motor of a conventionalconstruction and operating stroke. Once all of the storage stations inthe drive track have been filled, each operation of the tool results inthe driving of a fastener. By providing different numbers of storagestations, different amounts of clearance can be provided by thenosepiece structure. In one illustrated embodiment, the drive track andblade have a number of different width sections determined by the numberof storage sections, and in another illustrated embodiment any number ofstorage sections can be provided using drive track and driverwidths ofonly two different values.

Many other objects and advantages of the present invention will becomeapparent from considering the following detailed description inconjunction with the drawings in which:

FIG. 1 is a side elevational view in partial section of a fastenerdriving tool embodying the present invention; FIG. 2 is an enlargedsectional'view of the nosepiece structure embodied in the tool shown inFlG. l and illustrating the drive system for the tool in a normalconditionprior to operation of the tool;

FIG. 3 is a view similar to FIG. 2 illustrating the tool after a singlecycle of operation;

FIG. 4 is a view similar to FIGS. 2 and 3 illustrating the nosepieceassembly at the end of a powerstroke during a second or subsequentoperating cycle of the tool;

FIG. 5 is an enlarged sectional view taken along line 55 in FIG. 3;

FIG. 6 is a front elevational view of the nosepiece assembly shown inFIG. 4;

FIG. 7 is a sectional view taken along line 77 in FIG. 2;

FIG. 8 is a sectional view similar to FIGS. 24 but illustrating anosepiece structure having a number of fastener storing assemblies;

FIG. 9 is a seectional view taken along line 99 in FIG. 8;

FIG. 10 is a fragmentary sectional view of a modification of the toolshown in FIGS. 1-7 using a driver blade of a different configuration;

FIG. 1 l is an enlarged sectional view taken along line ll-l1 in FIG.10;

FIG. 12 is an enlarged sectional view taken along line 1212 in FIG. 10;

FIG. 13 is a fragmentary sectional view of another embodiment of thenosepiece structure of another tool embodying the present invention;

FIG. 14 is an enlarged sectional view taken along line 14-14 in FIG. 13;and

FIG. 15 is an elevational view of the back of the nosepiece structureviewed in the direction of line 1515 in FIG. 13.

Referring now more specifically to FIG. 1 of the drawings, therein isillustrated a pneumatic fastener driving tool which embodies the presentinvention and which is indicated generally as 10. The tool 10 is insubstantial part a conventional manually manipulated and pneumaticallyactuated staple driving tool having a housing 12 with a rearwardlyextending handle 12A affording a compressed air reservoir. When atrigger 14 is actuated to control a control valve assembly 16,pressurized air from the hollow handle 12A operates a pneumatic motorindicated generally as 18 to drive a fastener supplied by a magazineassembly indicated generally as 20 through a drive track in a nosepieceassembly indicated generally as 22 into a workpiece, such as a workpieceindicated generally as 24 (FIG. 4). The construction of the nosepieceassembly 22 and of a fastener driving blade 26 actuated by the motor 18and slidable in the nosepiece 22 is such that the motor 18 can be of aconventional or short stroke construction, even though the nosepiecestructure 22 is greatly elongated. This permits most of the componentsof the fastener driving tool 10 to be of a conventional constructionused in hand tools and obviates the need for a special motor having along stroke.

In accordance with the present invention, this is accomplished byproviding a modified and lengthened driver blade 26 with separateportions for moving fasteners through different parts of the nosepiecestructure 22 and by providing one or more fastener storing or retainingassemblies such as an assembly indicated generally as 28 in FIGS. 2-4.When the tool 10 is first operated, a fastener is transferred from themagazine assembly 20 to the storage assembly 28 in the nosepiecestructure 22. On the next cycle of operation of the motor 18, thefastener in the storage station 28 is driven into the workpiece 24, andconcurrently there+ with another fastener is transferred from themagazine assembly 20 to the storage assembly 28. On all succeedingcycles of operation of the tool 10, one fastener is driven into theworkpiece 24 and another fastener is transferred to the storage stationor assembly 28. In this manner, fasteners from the magazine 20 are fedin increments through the nosepiece 22 to be driven into the workpiece24 by a series of cycles of operation of the conventional pneumaticmotor 18.

An indicated above, a substantial number of the components of the tool10 can be of conventional construction. As an example, the illustratedtool 10 can comprise the pneumatically actuated tool for driving staplesshown and described in detail in U.S. Pat. No. 3,638,532. As shown inthis patent, the motor can comprise a cylinder 30 in which is slidablymounted a piston 32, to the lower end of which the upper end of thefastener driving blade 26 is secured. Movement of the piston 32 throughan operating cycle including a power stroke and a return stroke iscontrolled by the control valve assembly 16 such as the comparable unitillustrated in the above-identified patent. The assembly 16 is such thatthe tool 10 cannot be operated unless both the trigger 14 is elevatedand a safety stem 34 is moved downwardly (FIG. 1 When the lower end of asafety member or yoke 36 is moved upwardly by engagement with theworkpiece 24 (FIG. 4), a pivotally mounted link 38 moves a connectingelement 40 coupled to the stem 34 downwardly to depress the safety stem34 and enable operation of the control unit 16 under the control of themanual trigger 14.

If the trigger 14 is depressed with the safety stem 34 in its lowerposition, a top valve (not shown) for the cylinder 18 is opened to admitpressurized fluid to the upper interior of the cylinder 18. This movesthe piston 32 downwardly through a power stroke. When this pistonreaches a lower position determined by engagement with a resilientbumper 42, compressed air above the piston 32 passes through a passage44 in this piston and a passage 46 in the cylinder 30 to be accumulatedwithin a storage return chamber 48. When the control valve assembly 16is released, either automatically in a single stroke tool or by releaseof the safety member 36 or the trigger l4, compressed air above thepiston 32 within the cylinder 30 is vented to the atmosphere, and thepressurized air contained within the return space 48 enters the cylinder30 below the piston 32 through one or a number of ports 50. Thispressurized air serves to restore the piston 32 to its normal condition.

The tool 10 can be arranged to drive any suitable type of fasteners suchas staples or nails. In the illustrated tool 10, the magazine assembly20 includes a pusher 52 continuously resiliently biased by a tensionspring 54 to advance a strip of U-shaped staples 56 (FIG. 2) toward thenosepiece structure 22 by sliding movement supported on a rail 58, theforward end of which is carried on a shear block or member 60 rigidlysecured to the housing 12 for the tool 10. The strip of staples 56 andthe other components of the magazine assembly 20 are enclosed in asuitable housing 62 (FIG. 1). However, the construction of the magazine20 can be of any of a number well known in the art and can be such as tofeed not only the staples 56 but also nails, brads, and other fasteners.

The nosepiece structure 22 is, in general, formed by a front wallstructure or member 64 and a rear wall structure or member 66 which aresecured together and to the housing 12 and the magazine assembly todefine a drive track 68 having an upper portion 68A (FIG. 2) of greaterwidth and a lower portion 688 of a lesser width. The upper end of thefront wall member 64 is secured to a depending portion of the housing 12as by a pair of machine screws 70 (FIG. 6). The upper portion of thefront wall structure 64 also includes a rearwardly extending tab or wing64A (FIG. 1) which is secured to the magazine assembly 20, as by machinescrews 72. A pivot pin 74 carried on the rearwardly projecting portion64A pivotally supports the pivotal link 38 in the operating mechanismdescribed above for the safety stem 34.

The front wall member 64 also provides a slidable support for the safetylink or operator 36. As illustrated in FIG. 6, the front wall isprovided with a raised central portion 64B and two opposed pairs ofprojecting lugs 64C spaced from the central portion 648. The legs of aU-shaped lower end or work engaging portion 36A of the safety operatingelement 36 lie between the central raised portion 64B and the lower pairof lugs 64C with a plate 76 secured in an overlying relation by amachine screw 78 so as to slidably mount the lower end of the member 36on the front wall 64. An upper portion of the element 36 lies in thegroove defined by the raised portion 64B and the left-hand one of theupper lugs 64C and is slidably mounted therein by an overlying plate 80secured to the front wall 64 by a machine screw 82. An upper end portion36B of the touch-trip member 36 is offset to protrude through an openingin one end of the link 38 to provide a pivotal coupling therebetween.The operator element 36 is shown in an actuated position in FIG. 6.

As set forth above, the drive track 68 including the greater width upperportion 68A and the lesser width lower portion 68B is defined by thefront and back wall structures 64 and 66 in combination with portions ofthe structure of the tool 10, such as the block 60. The drive track 68is primarily defined by a centrally disposed slot milled or otherwiseformed in the rear surface of the front wall member 64 (see FIG. 5) andwhich is closed by the block 60 and the rear wall structure 66. Thegreater width portion 68A is defined between the slot and the facingwall of the block 60 (FIGS. 2-4) and a recess 86 formed in the frontsurface of the back wall member 66 (FIGS. 2-5). The narrow portion 688of the drive slot 68 is defined by a plate portion 66A (FIGS. 2-4 and 7)which fits within the slot formed in the rear surface of the front wallmember 64. In this connection, it should be noted that the portion 66Aprojects out of the plane of the rear wall member 66 and into the slotformed in the rear surface of the front wall member 64.

The fastener or staple storage or retaining assembly 28 is carried onthe rear wall member 66 disposed within the recess 86. This assemblyreceives a staple 56 from the magazine assembly 20 during one stroke ofthe fastener driving blade 26 and transfers this staple or fastener 56to a position in which it is driven into the workpiece 24 by the driverblade 26 during the next stroke of the pneumatic motor 18. The assembly28 includes a pair of generally channel-shaped staple retaining andbiasing members 88 and 90 (FIGS. 2-5 and 7) disposed within the recess86 and independently biased toward the front wall of the drive track 68by three conical compression springs 92, 94, and 96 interposed betweenthe adjacent wall of the rear wall structure 66 and the back walls ofthe elements 88 and 90, respectively. The member 88 is provided toprevent upward movement of a staple 56 disposed in the assembly 28, andthe member is provided to rceive a staple 56 from the magazine assembly20 on one stroke of the driver blade 26 and to transfer this staplewithin the drive track 68 to a position in which it will be driven intothe workpiece 24 on the next cycle of operation of the tool 10.

To this end, the member 88 includes a pair of projecting and downwardlyand inwardly inclined or tapered side walls 88A (FIGS. 2 and 7) spacedfrom each other a distance substantially equal to the separation betweentwo spaced depending legs 56A of the U- shaped staples 56. The two camor inclined portions 88A are spaced from each other by a somewhatchannel-shaped space shown as 888 in FIG. 7.

The second retaining element 90 is also channelshaped and includes twoupstanding edge portions 90A whose upper ends 90B are inclineddownwardly and inwardly toward the front wall of the drive track 68. Theportions 90A, 90B of the members are spaced apart approximately the samedistance as the depending legs 56A of the staple 56 to define anintervening channel or space indicated as 90C (FIG. 7).

To provide means for setting the normal position of the elements 88, 90of the storage assembly 28 and to provide means for pre-assembling thecomponents of the assembly 28 on the wall structure 66, the member 88 isprovided with two outwardly projecting tabs 88C (FIG. 7), and the member90 is provided with two pairs of opposed tabs 90D. The tabs 88C and 90Dare disposed within extensions 86A of the recess 86 in the back wallmember 66. Two thin spacers or plates 98 (one of which is illustrated inFIG. 7) are secured by machine screws 100 to the inner wall surface ofthe back wall structure 66 on opposite sides of the recess 86 so as tooverlie the ears or lugs 88C and 90D on the two members 88 and 90. Theplates 98 secure the members 88 and 90 in their desired normal positionagainst the resilient bias provided by the compression springs 88, 94,and 96. The use of the plates 98 permits the retaining assembly 28 to beassembled on the back wall structure 66 as an integral subassembly.

This subassembly is then secured to the front wall.

structure 64 by placing the structure 66 in the position shown, forexample, in FIG. 2, and securing the wall sections 66 and 64 together bymachine screws passing through a plurality of openings 102 (FIG. 7) inthe rear wall structure 66, the openings 102 also passing through thespacers or retaining plates 98. The back surface of the front wallstructure 64 is relieved to accommodate the heads of the fasteners 100,if necessary. The normal position of the elements 88 and 90 in theassembly 28 relative to the drive track 68 is illustrated in FIG. 2 ofthe drawings.

The lower end of the driver blade 26 is slidably received within thedrive track 68 and is provided with separate staple or fastener engagingsections of a stepped configuration. More specifically, the driver blade26 includes a first step or fastener engaging surface 26A (FIG. 2) of awidth approximately equal to the width of a crown portion 568 of theU-shaped staple 56. The length of the crown engaging surface 26A in adirection perpendicular to the plane of the drawing in FIG. 2 issomewhat less than the width of the spaces or channels 88B, 90C on theelements 88 and 90. The thickness of the driver blade 26 above the stepor contact engaging surface 26A is approximately equal to the width ofthe wide portion 68A of the drive track 68 or twice the width of one ofthe staples 56. In the normal position of the tool 10 or the pneumaticmotor 18, the contact engaging surface 26A is spaced slightly above thecrown 56B of the single staple 56 fed into the wide portion 68A of thedrive track 68 by the magazine assembly through a staple receivingopening indicated generally as 104. This opening 104 is defined by aclearance between the block 60, the housing 12 for the tool 10, and thehousing 62 for the staple magazine 20 in the usual manner. The positionof the staple 56 which is resiliently biased to the right (FIG. 2) bythe pusher 52 is set by engagement of the staple legs 56A and the staplecrown 56B with a portion 26B of the staple driver or staple drivingblade 26.

The portion 263 of the driver blade 26 terminates at I its lower end ina lower staple engaging surface indicated as 26C. The length of theportion 26B is such as to extend from the step or crown engaging portion26A to a point slightly above the lower edge of the member 88 in thestorage assembly 28. The width of the portion 26B of the blade 26 isapproximately equal to the width of the crown 56B of the staple 56 whichis also substantially equal, considering clearances, to the width of thenarrow portion 688 of the drive track 68. The length of the surface 26Cand also of the portion 26B in a direction perpendicular to the sheet inFIG. 2 is substantially equal to the corresponding dimension of thedrive track 68 which, in turn, is substantially equal to the length ofthe crown 56B measured in a direction perpendicular to the plane of thesheet in FIG. 2.

When the tool 10 is to be operated, a strip of staples 56 is placed inthe magazine assembly 20, and the resiliently biased pusher 52 advancesthe strip of staples 56 to the right so that the first staple 56 isdisposed in the position shown in FIG. 2 of the drawings which is set byengagement of this first staple 56 with the adjacent side surface of thedriver blade portion 268. In this position, the crown 56B of the firststaple underlies the crown engaging portion 26A on the driver blade 26.The tool 10 is then disposed on the workpiece 24 so that a stapledischarging opening 68C from the drive track 68 is disposed immediatelyadjacent or against the workpiece 24, and the U-shaped portion 36A ofthe safety link 36 engages the workpiece 24 to move the safety link oroperator 36 upwardly. As set forth above, this partially enables thecontrol valve assembly 16. The operator then actuates the trigger 14 sothat compressed air is supplied to the interior of the cylinder 30 abovethe piston 32 to initiate downward movement of this piston and theconnected driver blade 26.

During the first increment of downward movement, the surface 26A engagesthe crown 56B of the first staple 56 in the wide portion 68A of thedrive track 68 and severs this staple from the remainder of the staplestrip. During this movement of the driver blade 26, the next staple 56is not permitted to enter the drive track 68 through the opening 104because it bears against the upper portion of the driver blade 26.

Continuing downward movement of the driver blade 26 moves the lower orfree ends of the staple legs 56A into engagement with the downwardlyinclined walls 88A on the retaining member 88 so that this member iscammed or displaced to the left in FIG. 2 against the bias of thecompression spring 92 and held in this displaced position as the staplelegs 56A pass beyond and by the lower ends of the inclined surfaces 88A.The lower free ends of the staple legs 56A next contact the inclinedsurfaces 908 on the member 90 to displace this member to the left (FIG.2) against the bias of the compression springs 94, 96. Thereafter, thesides of the staple legs 56A slide along the parallel surfaces on theedge portions 90A of the member 90 disposed between these surfaces andthe flat rear surface of the blade portion 268.

At the end of the normal or short operating stroke of the pneumaticmotor 18 determined by the engagement of the piston 32 with theresilient bumper 42, the driver blade 26 is in the position illustratedin FIG. 4. In this position, the narrow portion of the blade 26 abovethe crown engaging surface 26A is slidably disposed between the inclinedside walls 88A on the member 88. When the crown 568 has moved to theposition shown in FIG. 4, the compression spring 92 moves the remainingmember 88 to the right (FIG. 4) so that the lower edges of the sidewalls 88A overlie the crown 56B of the first staple. Thus, the member 88provides a latch preventing upward movement of the first staple 56. Atthis time, the compression springs 94, 96 bias the element 90 to theright so that the staple legs 56A are held against the rear surface ofthe driver blade portion 26B in the position shown in FIG. 4. The lowerdriving surface 26C of the driver blade is flush with or projectsslightly beyond the opening 68C at the lower end of the narrow portion68B of the drive track but does not drive a staple 56 inasmuch as nostaples have been provided as yet to this portion of the drive track 68.

When the control valve assembly 16 is released, the piston 32 iselevated to its illustrated normal position shown in FIG. 1 in themanner described above. The staple 56 remains in the position shown inFIG. 4 even though this staple is biased against the upwardly movingblade portion 268 because of the detent provided by the lower edges ofthe side walls 88A on the member 88. When the lower end of the driverblade portion 268 clears or passes upwardly beyond the crown 56B of thestaple in the storage means 28, the compression springs 94, 96 move themember 90 to the right to the position shown in FIG. 3 so that the crown56B of the staple 56 is moved from beneath the lower edge of the member88, and the edge surfaces of the staple 56 are biased against the frontwall of the drive track 68 defined by the rear wall of the front wallstructure 64. 'At substantially the same time, the surface 26A clearsthe crown 56B of the next staple in the strip of staples in the magazineassembly 20, and an additional staple 56 is moved into the wide portion68A of the drive track 68 beneath the crown engaging surface 26A on thedriver blade 26, as illustrated in FIG. 3.

Thus, the second staple to be driven is now biased against the driverblade portion 263 with its corwn 56B underlying the driver blade surface26A, and the first staple 56 to be driven is also disposed in the wideportion 68A of the drive track 68 with its crown 56B disposed beneaththe driving surface 26C at the lower end of the driver blade portion26B. This staple 56 in the storage section 28 is removably retained inthis position by the resilient bias of the compression springs 94, 96supplied through the retaining member 90. The tool 10 remains in thiscondition until such time as the next cycle of operation is initiated.

When the control 16 initiates the next power stroke of the pneumaticmotor 18, the piston 32 and the connected driver blade 26 again movedownwardly from the position shown in FIG. 2. At this time, the fullwidth crown engaging surface 26C at the lower end of the driver bladeportion 268 engages the crown portion 568 of the staple 56 held in thestorage section 28 and moves the legs 56A of this staple downwardly intothe narrow portion 688 of the drive track over the slight resistance ofthe resilient bias provided by the springs 94, 96. At the completion ofthe full stroke of the motor 18, the first staple 56 has been dischargedfrom the drive track 68 through the opening 68C and driven into theworkpiece 24 as illustrated in FIG. 4. At the same time, the surface 26Asevers the endmost or second staple 56 from the strip thereof and movesthis staple to the storage section 28 in the manner described above.Thus, at the termination of the second power stroke of the pneumaticmotor 18, the components are in the position illustrated in FIG. 4.

The release of the control valve 16 causes the retraction of the piston32 and the driver blade 26 so that the tool is then placed in thecondition shown in FIG. 3 in which the third staple 56 in the strip isdisposed beneath the driving surface 26A, and the secnd staple 56 isheld in the storage section or assembly 28 with its crown 56B disposedbeneath the driver surface 26C. Thus, on each successive operation ofthe tool 10, a staple supplied by the storage section 28 is driven intothe workpiece 24, and an additional staple 56 is transferred from themagazine assembly 20 into the storage section or assembly 28. All ofthis is accomplished with a stroke of the pneumatic motor 18 that isapproximately one-half of the stroke previously required for nosepiecestructures of the length afforded by the illustrated nosepiece structure22.

FIGS. 8 and 9 of the drawings illustrate a nosepiece structure 110embodying the present invention and affording an even greater clearancethan the nosepiece structure 22 but capable of being used with thepneumatic motor 18 without a change in the operating stroke thereof. InFIGS. 8 and 9 components similar or identical to the components in theembodiment shown in FIGS. 1-7 are identified by like reference numbers.In general, the nosepiece structure 110 utilizes a pair of staplestoring or retaining assemblies identical to the assembly 28 anddesignated in FIG. 8 by the reference numbers 28 and 128 and a modifieddriver blade 112. Using the nosepiece structure 110, three cycles ofoperation of the tool are required to transfer a staple 56 from themagazine 20 to the workpiece 24 because the staple 56 must pass insequence through the two staple storing sections 28 and 128.

The nosepiece structure 110 includes a drive track indicated generallyas 114 having an upper greatest width portion 114A, an intermediatelesser width portion 114B, and a lower narrowest width portion 114C. Thewidths of the portions l14A-ll4C differ from each other by dimensionsgenerally equal to the width of the staple 56. The front and side wallsof the drive track 114 are defined by the front wall member 64, and therear wall is defined by the block 60 and the rear wall structures 66 ofthe two storage assemblies 28 and 128. Although the front wall structureis identified by the reference number 64, it is obvious that the lengthof this structure is greater than the front wall 64 in the nosepiecestructure 22 because of the greater length of the nosepiece assembly110. Further, the rear surface of the front wall structure 64 to whichthe back wall structure66 is secured may be provided with steps so thatwhen the two structures 66 carrying the assemblies 28 and 128 aresecured thereto, changes in the width or thickness of the drive trackportions 1148 and 114C can be obtained. On the other hand, by changingthe thickness of the retaining plates 98 secured to the wall structures66, the same change in the width or thickness of the drive tracksections 114B and 114C can be obtained using a planar rear surface onthe front wall member 64.

The components of the nosepiece structure 110 are secured or joinedtogether and to the housing 12 of the tool 10 in the same manner as thenosepiece structure 22. As an example, threaded fasteners or machinescrews extend through an upper portion of the front wall structure 64 tobe threadedly received within a depending portion of the housing 12(FIG. 9). The wall structures 66 are secured to the edge portions of thefront wall structure 64 by threaded fasteners passing through openingscorresponding to the openings 102 shown in FIG. 7. By usingsubstantially identical assemblies 28 and 128 to provide the nosepiecestructure 110, the inventory required to provide tools 10 withnosepieces of different lengths is reduced.

The driver blade 112 which is connected to and moved by the piston 32 inthe pneumatic motor 18 is longer than the driver blade 26 by an amountapproximately equal to the length of one of the rear wall structures 66measured in its direction of elongation. The blade 112 is slidablyreceived within the drive track 114. To provide means for movingfasteners or staples 56 from the staple receiving opening 104 along thedrive track 114, the driver blade 112 includes portions of three widthsor thicknesses 112A, 1123, and 112C slidable respectively, within thethree different width portions 114A, 114B, and 114C of the drive track114. Each of these portions 1l2A-1 12C differs from each other in widthapproximately the width of one of the staples 56. Each of the differentwidth portions 1 12A-112C terminates in a staple crown engaging portionor surface ll2D-112F, respectively, with the surface 112D being disposedimmediately above the crown 563 on a staple fed by the magazine assembly20, with the surface 112E disposed immediately above the crown 56B ofthe staple in the first storage section 28, and with the surface 112Fdisposed immediately above the crown 56B of a staple 56 in the secondstorage assembly 128. The portions 112A and 1123 immediately above thecrown engaging surfaces 112D and 112E are reduced in dimension in adirection perpendicular to the sheet in FIG. 8 to a value somewhat lessthan the spaces or channels 88B, C on the elements 88 and 90 so that theindicated portions of the driver blade 112 do not engage members 88 and90. This reduction is illustrated in FIG. 9.

When the tool 10 containing the nosepiece structure is placed againstthe workpiece 24 to elevate the safety operator 36, the operation of thetrigger 14 to actuate the motor through its first power stroke moves theblade 112 downwardly so that the surface 112D moves the first staple 56from the position illustrated in FIG. 5 to be stored in the firststorage assembly 28. When the blade 112 is retracted, the element 88 inthe assembly 28 prevents return movement of the staple 56. Thus, whenthe middle width portion 1128 of the blade 112 clears the staple 56 inthe assembly 28, the element 90 in this assembly shifts the first staple56 into engagement with the portion 112C of the blade 112 beneath thecrown engaging surface 11215.

When the pneumatic motor 18 is next operated, the surface 112D moves thesecond staple 56 into the first storage section 28, and the surface 112Emoves the first staple into the storage section 128. When the driverblade 112 is retracted at the end of this second stroke, the element 90in the assembly 28 shifts the second staple against the blade portion112C with its crown 56B beneath the surface 11213. The element 90 in theassembly 128 shifts the first staple against the front wall of the drivetrack 114 beneath the crown engaging surface 112F.

When the tool is operated for the third time, the surface 112D moves thethird staple56 from the strip into the first storage section 28, thesurface 112E moves the second staple from the storage assembly 28 intothe storage assembly 128, and the surface 112F engages the crown 56B ofthe first staple 56 to drive this staple through the narrow width drivetrack portion 114C into the workpiece 24. When the blade 112 isretracted, the second staple 56 from the magazine is moved under thesurface 112F, the third staple 56 from the magazine is fed beneath thesurface 112E, and the fourth staple 56 from the strip is advancedthrough the opening 104 into the drive track 114 to abut the driverblade portion 1128 with its crown 56B disposed beneath the surface 112D.Thereafter, each actuation of the tool 10 drives a staple 56 into theworkpiece 24 and transfers staples 56 between the magazine assembly 20and the storage sections 28 and 128.

FIGS. 10-12 of the drawings illustrate a nosepiece structure which isindicated generally as 130 and which embodies the present invention. Thenosepiece structure 130 is similar to the nosepiece structures 22 and110 described above and can use fasteners such as the staples 56.However, the nosepiece structure 130 and an accompanying driver 132 canalso be used with staples in which the crown portion is not planar orperpendicular to the staple legs. As an example, the nosepiece structure130 can be used with staples having a crown portion that is pitchedupwardly. The nosepiece structure 130 forms a part of the tool 10 andcan be such as to include only a single storage section. The arrangementillustrated in FIGS. 10-12 is, however, designed for use with a toolhaving two storage sections and requiring three strokes to drive astaple in the manner of the nosepiece structure 110 shown in FIGS. 8 and9. In FIGS. 10-12, those parts of the tool 10 that are similar to thosedescribed above are identified by like reference numbers.

In general, the nosepiece structure 130 is constructed in the samemanner as the nosepiece structure or as" sembly 110 and is coupled orsecured to the housing 12 of the tool 10 as well as to the magazineassembly 20. The constructions of the driver blade 132 and a drive track134 in which the blade 132 is slidably mounted are modified from thoseshown in FIGS. 8 and 9. The blade 132 drives a staple 56 supplied fromthe magazine assembly 20 into a workpiece after a sequence of threedriving strokes of the piston 32 in the pneumatic motor 18 to which theupper end of the driver blade 132 is connected. The nosepiece structure130 includes two storage assemblies or stations 136 (only one of whichis illustrated in FIG. 10) spaced along the drive track 134 in positionscorresponding to the storage stations 28 and 128 in the nosepiecestructure 110. Each of the storage stations or assemblies 136 isidentical to the storage assembly 28 except for the means providedtherein for preventing retrogressive movement of the staple 56.

The driver blade 132, the upper end of which is coupled to the piston 32in the pneumatic motor 18, is formed in part with a generally U-shapedor channelshaped configuration (FIG. 11) and includes a flat bight orbase portion 132A of sectional dimensions generally corresponding to theplanar dimensions of the crown portion 568 of a staple 56. Oppositeedges of the upper portion of the driver blade 132 are provided withtransversely projecting or upstanding legs 132B stepped to provideportions of two different heights, each one terminating in a pair oftransversely aligned crown engaging shoulders 132C and 132D,respectively.

The pair of shoulders 132C (FIG. 10) are normally disposed just abovethe crown 56B of the staple supplied through the opening 104. The pairof shoulders 132D on the projecting edges 132B are spaced below theshoulders 132C a distance approximately equal to the stroke of thepiston 32 and normally overlie the crown portion 568 of a staple storedin the assembly 136. The lower end of the planar base portion 132A ofthe blade 132 provides a means for transferring a staple 56 from thesecond storage assembly 136 (not shown) to the workpiece and is spacedbelow the pair of shoulders 132D a distance approximately equal to thestroke of the piston 32. Since the shoulders 132C and 132D engage thestaple crown 56B adjacent its opposite ends in positions generallyaligned with the staple legs 56A, the intervening center of the crown56B need not be flat and can, for example, be upwardly dished or bowed.

The drive track 134 (FIG. 1 l) is primarily defined by a recess formedin the back surface of the front wall structure 64 which is closed by aportion of the housing 12, the shear block 60, and the rear wallstructures 66 of the two storage assemblies 136 in the same manner asthe drive tracks 68 and 114. However, the configuration of these partsis changed to provide U-shaped portions in the drive track 134 toreceive the like formed parts of the driver blade 132. The rear wallstructures 66 for the two storage assemblies 136 provide drive trackportions of three progressively smaller widths as in the drive track 114for the nosepiece structure 110. The length of the drive track 134measured from the opening 104 to a staple discharging opening is aroundthree times the length of the stroke of the pneumatic motor 18, the sameas the length of the drive track 114, and longer than the length of thedrive track 68 which is twice the length of the stroke of the motor 18.

Since the crown 56B of each staple S6 to be advanced through thenosepiece structure is engaged at its ends in general alignment with theupper ends of the staple legs 56A, each of the storage assemblies 136 ismodified so that the retaining means provided therein for preventingretrogressive movement of the staple 56 during the return stroke of theblade 132 engages the central rather than the edge portions of thestaple crowns 56B. More specifically, the storage or transfer assembly136 is identical to the assembly 28 described above except for theconstruction or configuration of a staple retaining element 138 (FIGS.and 12). The element 138 is generally planar in configuration andincludes offset opposite end portions or tabs 138A (FIG. 12) disposedwithin the recesses 86A and adapted to be biased against the locatingplates 98 by the interposed compression spring 92 (FIG. 10). However,the retaining member 138 is provided with an upstanding central portion'138B (FIGS. 10 and 12) having an upper surface that tapers downwardlyand inwardly (FIG. 10). The upstanding portion'l38B is narrow enough tobe freely movable within the channel spaced area disposed between theupstanding legs 1328 on the driver blade 132.

Accordingly, when a strip of staples 56 is placed in the magazineassembly 20, its forward portion is disposed within the opening 104, andthe first staple 56 is biased against the intermediate height portion ofthe two legs 132B with the staple legs 56A on this first staple disposedagainst the aligned edges of the intermediate height portion of the legs132B. Thus, the crown 56B on the first staple 56 underlies the pair ofshoulders 132C. When the piston 32 first moves downwardly, the shoulders132C engage the crown portion 56B at its two opposite ends and separatethis staple from the strip of remaining staples 56.

Continuing downward movement of the piston 32 moves the separatedstaple56 downwardly through the widest portion of the drive track 134 so thatthe staple legs 56A engage the inclined surfaces 90B on the member 90 inthe first storage assembly 136 and shift this member to the left againstthe bias of the compression springs 94, 96. These legs are then movedinto a position interposed between the fiat edge surface of the spacedlegs 90A on the member 90 and the edges of the intermediate heightportion of the legs 132B on the driver blade 132. i

As the crown 56B of this staple moves into the station 136, it engagesthe inclined surface on the projecting portion 1388 and cams the element138 to the left (FIG. 10) against the bias of the spring 92. The legs132B on the driver blade 132 pass by the projecting portion 138B. Whenthe staple crown 56B moves downwardly below the lower edge of theretaining member 138, the lower edge of the projecting portion 138Bsnaps over the crown 56B on the first staple 56.

When the pneumatic motor 18 initiates its return movement, the bearingof the lower edge of the projecting portion 138B on the central portionof the crown 56B prevents return or retrogressive movement of thisstaple. As the blade 132 moves upwardly toward its normal position, thecompression springs 94 and 96 act on the member 90 to transfer the firststaple 56 to the right so that it bears against the base portion 132A ofthe driver blade 132 with the crown 56B of the first staple 56 disposedbeneath the spaced shoulders 132D.

At the end of the return movement of the blade 132, the second staple 56moves into the widest portion of the drive track 134 with its crownbelow the spaced shoulders 132C. The tool remains in this conditionuntil it is next operated.

At this time, the shoulders 132C transfer the second staple 56 from thestrip into the illustrated assembly 136, and the shoulders 132D transferthe first staple 56 from the illustrated storage station 136 to the nextsubsequent station 136 (not shown) along the drive track 134 and locatedin an intermediate width portion of this drive track. When the driverblade 132 is retracted at the end of this second cycle of operation, thethird staple 56 is moved beneath the shoulders 132C, the secondv stapleis moved beneath the shoulders 132D, and the member in the secondstorage station 136 (not shown)moves the first staple 56 beneath thelower end of the flat base portion 132A of the blade 132. Accordingly,on the next cycle of operation of the tool 10, the third staple from thestrip is moved into the storage station 136, the second staple is movedinto the lower storage station 136, and the first staple from the stripis driven through the narrow portion of the drive track 134 into theworkpiece 24. Thereafter, each operation of the tool 10 results indriving a staple 56.

FIGS. 13-15 of the drawings illustrate a nosepiece structure whichembodies the present invention and which is indicated generally as 140.The nosepiece structure is adapted to be used with the tool 10 and issecured to both the housing 12 and the magazine assembly 20 to providemeans for driving staples supplied from the assembly 20 through theopening 104 into a workpiece by operating the pneumatic motor 18 througha plurality of strokes. In the nosepiece assembly 140, a drive track 142in the nosepiece structure 140 requires only two different widths orthicknesses regardless of the number of staple storing sections orassemblies provided along the length of the drive track 142. Theillustrated nosepiece structure 140 includes a pair of fastener orstaple storing assemblies 144 and 146 so that three cycles of operationof the pneumatic motor 18 are required to advance any given staple 56from the magazine assembly 20 to a workpiece. The drive track 142 andthus a driver blade 147 coupled to the piston 32 and slidable within thedrive track 142 can be formed having only two effective widths orthicknesses by forming the components of the transfer 'assemblies 144and 146 of flexible resilient members.

The drive track 142 is defined by a front wall member 148 on the rearsurface of which is integrally formed or secured a rear wall structure150. The drive track 142 is primarily defined by a slot in the rearsurface of the front wall 148 (FIG. 14) of sectional dimensionsapproximately equal to the planar dimensions of the staple crown 56B.The length of the drive track 142 measured from the opening 104 to itslower end is around three times the length of the stroke of thepneumatic motor 18. The open side of the slot in the front wall 148 isclosed by a portion of the housing 12, by the shear block 60, and therear wall structure 150 so that the greater portion of the drive trackhas a wide or greater width or thickness indicated at 142A (FIG. 13)approximately corresponding to the width of two staple crown portions568. A lower portion 1428 of the drive track 142 has a widthapproximately equal to the width or thickness of a single staple crown568.

The rear wall structure 150 (FIGS. 13 and 15) includes a longitudinallyextending slot shown generally as 152 that throughout a greater portionof its length is approximately equal to the width of the slot in thefront wall 148. At its lower portion indicated as 152A and generallycorresponding to the portion 1423 of the drive track, the slot 152 is ofless width than the slot or recess in the front wall 148 to provide apositive support for the staple legs 56A as they are driven into theworkpiece. The slot 152 is interrupted substantially midway along itslength by a bridging wall portion 150A on the back wall structure 150.

The driver blade 147 includes a base portion 147A of generally the samewidth and thickness as the narrow portion 1428 of the drive track whichextends from a staple engaging or driving surface 1478 (FIG. 13)throughout its length to its point of connection to the piston 32 in thepneumatic motor 18. Superimposed on and formed integral with the baseportion 147A are a pair of projecting portions 147C and 147D (FIGS. 13and 14) which terminate in shoulders 147E and 147E respectively, adaptedto engage centrally disposed portions of the staple crowns 568. Theprojecting portions 147C and 147D are adapted to move within the greaterwidth portion 142A of the drive track, and their points of greatestthickness at the shoulders 147E and 147F are approximately equal to thewidth of the staple crown 56B. The shoulders 147E, 147F and the drivingsurface 147B are spaced apart approximately the length of the stroke ofthe motor 18.

As noted above, the back wall structure 150 is opened by the slot 152substantially throughout its length. The staple storage assemblies 144and 146 provide means for not only retaining and transferring staples 56at spaced positions along the drive track 142 during operation of thetool but also provide means for selectively closing the back wall of thedrive track 142. The assemblies 144 and 146 are carried on a generallyU-shaped supporting bracket 160 so that a bight portion 160A of themember 160 is spaced from and disposed generally parallel to the backsurface of the back wall structure 150. The two side walls of theU-shaped member 160 are secured to one or both of the drive trackdefining wall structures 148 and 150.

The staple storing assembly 144 is formed by a flexible and resilientmember 162 having one end secured by a rivet 164 against the innersurface of the bight portion 160A of the supporting bracket 160. Themember 162 has a width approximately equal to the width of the drivetrack 142 and is generally U-shaped in configuration so that anintermediate portion 1628 (H6. 13) is disposed within the slot 152 inthe back wall member 150 overlying the adjacent portion of the driverblade 147. The portion 1628, in addition to guiding movement of thestaple 56, provides means for transferring this staple to a position inwhich its crown 56B is disposed beneath the shoulder 147F on the driverblade 147.

To aid adequate guiding or positioning of the staple legs 56A within thedrive track 142, the slot 152 is pro vided with two vertically spacedand opposed pairs of enlargements identified as 1528 (FIG. 15). The webportion 162B is provided with two longitudinally spaced and opposedpairs of projections or tabs 162C which project outwardly into therecesses 1528. The member 162 is prestressed to bias the web portion162B toward the front wall structure 148, and the engagement of the tabs162C with the adjacent surface of the back wall structure 150 forms astop to properly position the web portion 1628 with respect to the drivetrack 142.

The free end of the member 162 is offset angularly away from the planeof the drive track 142 and is provided with a pair of offsets,projections, or ears 162D. The lower edges of the ears 162D are adaptedto engage the staple crown 568 to provide means for preventingretrogressive movement of a staple 56 within the drive track 142. Theears 162D are spaced apart a distance slightly greater than the width ofthe projections 147C and 147D so that these projections can slidebetween these ears.

The storage assembly 146 is formed of a pair of flexible resilientmembers 164 and 166. The member 164 is of a width substantially equal tothe width of the drive track 142 and includes an upper end portion 164Athat is secured against the outer wall of the bight portion 160A of thesupporting bracket 160 by a rivet 168. A free lower end portion 16413 ofthe member 164 is disposed within the slot 152 to define a portion ofthe back wall of the drive track 142 and to provide means for releasablyretaining a staple 56 beneath the lower end or staple engaging surface1478 of the driver blade 147.

To insure proper guiding or positioning of the staple legs 56A as theymove through theportion of the drive track 142 closed by the secondstorage assembly 146, the slot 152 in the back wall of the back wallstructure 150 includes a pair of opposed recesses or relieved portionsindicated as 152C (FIG. 15). The free end portion 1648 of the resilientmember 164 includes a pair of outwardly projecting lugs or tabs 164Cwhich project into the recessed portions 152C. The engagement of thetabs 164C with the adjacent surfaces of the back wall structure 150serves as a stop to set the normal position of the web portion 1648which is prestressed or biased toward the front wall structure 148.

The member 166 provides a retaining member for preventing retrogrademovement of a staple 56 located in the assembly 146. An upper free endof the flexible resilient member 166 is secured adjacent the inner wallof the bight portion A of the bracket 160 by the rivet 168. The lowerfree end of the member 166 which is of a width substantially less thanthe width of the member 164 is formed with a pair of offset andprojecting ears or lugs 166A, the lower edges of which are adapted toengage the crown 56B of a staple in the assembly 146 to prevent returnmovement of this staple. The space between the lugs or ears 166A on themember 166 is slightly greater than the width of the projecting portion147D on the driver blade 147.

To aid in positioning the free end of the retaining member 166containing the offset ears 166A, the lower edge of the bridging portion150A of the back wall member 150 is recessed or notched as shown at 1508(FIG. 13). The portion of the resilient member 166-containing the ears166A extnds at least partially through the notch 150B which aids inlocating this retaining means. The member 166 is prestressed to bebiased against the bridging portion 150A.

When the tool 10 is to be operated using the nosepiece assembly 140, astrip of staples 56 is placed in the magazine assembly 20 so that thefirst staple 56 is moved through the opening 104 into the wide portion142A of the drive track 142. In this position, the legs 56A and thecrown 56B bear against the base portion 147A of the driver blade withthe crown 56B disposed immediately below the shoulder 147E on theprojecting portion 147C. When the tool is operated and the driver blade147 begins to move downwardly, the shoulder 147E moves against the crown56B of the first staple and moves this staple downwardly through thewide portion 142A of the drive track. As the lower ends of the staplelegs 56A reach the storage assembly 144, the legs 56A engage anddisplace to the left the portion 162B of the resilient member 162. Asthe driver blade 147 reaches the end of its power stroke, the shoulder147E moves the crown 56B of the first staple into engagement with theinclined edges of the ears 162D so that this element is deflected to theleft and snaps back to the right so its lower edges overlie the crown56B. The projecting portion 147C passes between the ears 162D duringthis movement.

When the blade 147 moves upwardly, the ears 162D engage the crown 56B ofthe first staple now in the storage assembly 144 to prevent its upwardmovement, and the web portion 162B of the resilient member 162 biasesthe staple legs 56A against the base portion 147A of the driver blade147 as it is retracted. During this movement the protruding portion 147Don the driver blade passes between the legs 56A of the staple held bythe member 162 until such time as the inclined surface thereof begins tocam against the crown portion 568. This deflects the staple crown 56Band the upper portion of the resilient member 1628 carrying the ears162D to the left to permit the projecting portion 147D to clear or passby the crown 56B of the staple 56 held in the assembly 144. As theshoulder 147F passes by the crown 56B, the web portion 162B biases thesecomponents to the right to the position shown in FIG. 13. This placesthe crown 56B of the first staple 56 beneath the shoulder 147F on theprojecting portion 147D with the staple legs 56A pressed against thebase portion 147A by the web portion 1628.

When the driver blade 147 next moves downwardly, the second staple 56supplied through the opening 104 from the magazine assembly 20 movesdownwardly through the wide portion 142A of the drive track 142 and isdisposed in the first storage assembly 144 in the same manner as thefirst staple. During this movement, the shoulder 147F engages the crown56B of the first staple and slides this staple downwardly within thewide portion 142A of the drive track 142 against the bias provided bythe portion 1628 of the resilient member 162. As this first staple movesinto the second storage assembly 146, the legs 56A cam the lower portion16413 of the resilient member 164 to the left so that the staple 56 isheld against the base portion 147A of the driver blade 147. During thismovement the projecting portion 147D passes between the ears 166A on theresilient member 166 and moves the crown 56B on the first staple beneaththe lower edges of these cars.

When the return stroke of the second cycle of the pneumatic motor 18 isinitiated, the first staple 56 is held within the assembly 146 becausethe lower edges of the ears 166A engage the crown 56B of this staple. Asthe driver blade 147 approaches its normal position, the portion 164B ofthe resilient member 164 shifts the first staple 56 to the positionshown in FIG. 13 so that its crown 56B underlies the lower end drivingportion 1478 on the driver blade 147. Further, as the inclined surfaceon the projecting portion 147D of the blade 147 engages the crown 56B ofthe second staple now in the first storage assembly 144, this staple andthe member 162 are tipped to the left (FIG. 13) to permit the shoulder147D to pass by the crown 56B of this staple. When the shoulder 147D haspassed by the crown 563, the portion 1628 of the resilient member 162 6moves the engaged second staple 56 to the position shown in FIG. 13 inwhich its crown 56B underlies the shoulder 147F.

On the next or third power stroke of the motor 18, the shoulder 147Emoves the third staple 56 from the strip to the first storage assembly144, and the shoulder 147F moves the second staple 56 from the strip tothe second storage section 146. The lower end 147B of the blade 147 nowengages the crown 56B of the first staple and moves this staple againstthe bias of the resilient portion 1648 into the narrow portion 142B ofthe drive track 142 and out of this portion of the drive track into theworkpiece. At the completion of the return stroke of the driver blade147, the nosepiece structure is in the condition illustrated in FIG. 13.Thereafter, each cycle of operation of the pneumatic motor 18 results indriving the staple 56 stored in the storage assembly 146 and thetransfer of an additional staple from the magazine assembly 20 into thefirst storage assembly 144, the staple 56 therein being transferred intothe storage assembly 146.

Although the present invention has been described with reference to anumber of illustrative embodiments thereof, it should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the art which will fall within the spirit and scope of theprinciples of this invention.

What is claimed and desired to be secured by Letters Patent of theUnited States is:

1. A tool for applying fasteners to a workpiece comprising a drive trackassembly defining a drive track with a fastener receiving opening and afastener discharge opening and having fastener storage meanstherebetween,

a fastener driver slidable in the drive track and having separateportions for moving fasteners from the receiving opening through thestorage means to the discharge opening in separate steps,

and an operating means coupled to the fastener driver and operablethrough separate strokes during each of which one fastener is moved fromthe receiving opening to the storage means and another fastener is movedfrom the storage means through the discharge opening to be applied tothe workpiece,

said drive track assembly including at least one enlarged portion in thedrive track,

and the fastener driver including a corresponding enlarged portion.

2. A tool for applying fasteners to a workpiece comprising a poweractuated fastener driver movable through a given stroke between normaland displaced positions,

a drive track structure defining a drive track with a fastener receivingopening through which fasteners are supplied to the drive track and afastener discharge opening through which fasteners are discharged fromthe drive track to the workpiece, the fastener receiving opening and thefastener discharge opening being spaced from each other along the drivetrack a distance that is substantially an integral multiple of the givenstroke and greater in value than one, said fastener driver beingslidably mounted in the drive track,

and spaced fastener engaging portions on the fastener driver foradvancing successive fasteners through different portions of the drivetrack on successive strokes of the fastener driver,

to a workpiece comprising a power actuated fastener driver movablethrough a given stroke between normal and displaced positions,

a drive track structure defining a drive track with a fastener receivingopening through which fasteners are supplied to the drive track and afastener discharge opening through which fasteners are discharged fromthe drive track to the workpiece, the fastener receiving opening and thefastener discharge opening being spaced from each other along the drivetrack a distance that is substantially an integral multiple of the givenstroke and greater in value than one, said fastener driver beingslidably mounted in the drive track,

spaced fastener engaging portions on the fastener driver for advancingsuccessive fasteners through different portions of the drive track onsuccessive strokes of the fastener driver,

said drive track having a first portion of said given first widthadjacent the fastener discharge opening and a second portion between thefirst portion and the fastener receiving opening with a width greaterthan said given first width,

said second portion of the drive track including portions of second andthird widths greater than the first width,

and said fastener driver having portions of first, secnd, and thirdwidths slidably mounted in the first, second, and third width portionsof the drive track.

5. The tool set forth in claim 2 in which said second portion of thedrive track has a second width along its length,

and the fastener driver has one portion of the first width slidablymounted in the first portion of the drive track and spaced portions ofsaid second width slidably mounted in the second portion of the drivetrack.

6. A tool for applying fasteners to a workpiece comprising an elongatedfastener driver operable through an operating stroke between normal andactuated positions, said driver having a fastener driving portion at oneend and at least one fastener engaging transfer portion spaced above thefastener driving portion,

drive track structure defining a drive track in which is slidablymounted the fastener driver, said drive track having a lower portionslidably receiving the fastener driving portion of the fastener driveand an enlarged storage portion disposed above the lower portion andslidably receiving the transfer portion of the fastener driver,

fastener retaining means carried on the drive track structure anddisposed in the enlarged storage portion of the drive track forremovably retaining a fastener in the storage portion,

fastener feeding means for feeding fasteners into the drive track,

and operating means coupled to the fastener driver for actuating thefastener driver through successive strokes during which the transferportion of the fastener driver moves fasteners into the retaining meansin the storage portion and the fastener driving portion of the fastenerdriver moves fasteners from the storage portion into the workpiece.

7. A tool for driving elongated fasteners into a workpiece comprising adrive track structure defining a drive track and having a fastenerreceiving opening and a fastener discharge opening adapted to be placedadjacent the workpiece,

fastener driving means including a fastener driver movably mounted inthe drive track for movement through repeated strokes,

a magazine assembly for supplying a fastener through said receivingopening to the drive track on each stroke of the fastener driver,

and fastener storage means on the drive track structure between thefastener receiving opening and the fastener discharge opening forstoring a fastener between strokes of the fastener driver whereby morethan one stroke of the fastener driver is necessary to move a fastenerfrom the fastener receiving opening to the fastener discharge opening,

the fastener storage means including a number of fastener storageassemblies spaced from each other along the drive track, each assemblyadapted to store a single fastener.

8. The tool set forth in claim 7 in which each fastener storage assemblyincludes deflectable means removably retaining a fastener in a positionin the drive track spaced between the fastener receiving opening and thefastener discharge opening.

9. The tool set forth in claim 8 in which the deflectable means includesa rigid fastener engaging means and resilient biasing means acting onthe rigid fastener engaging means.

10. The tool set forth in claim 8 in which the deflectable meansincludes flexible resilient means engaging the fastener.

11. The tool set forth in claim 7 in which the fastener driver includesseparate fastener engaging portions for moving the fastener from aposition adjacent the fastener receiving opening through the storageassemblies to the fastener discharge opening.

12. A tool for driving fasteners into a workpiece comprising a nosepiecestructure defining a drive track extending from a fastener receivingportion to a fastener discharge opening with at least two drive trackportions of different widths between said receiving portion and saiddischarge opening,

fastener driver means slidable in the drive track and having separateand spaced fastener engaging por tions slidable in the different widthportions of the drive track,

fastener feeding means for feeding fasteners into the drive track at thefastener receiving portion,

and operating means for moving the fastener driver means throughrepeated strokes in the drive track to advance a fastenerfrom thereceiving station successively through the different width portions ofthe drive track on successive strokes of the fastener driver meanswhereby movement of the fastener through the drive track from thereceiving portion to the discharge opening requires more than one strokeof the fastener driver means.

13. A fastener driving tool for driving fasteners into a workpiececomprising a nosepiece structure including spaced front and back wallsjoined by side walls defining a drive track, a lower end of the drivetrack terminating in a discharge opening and the spacing between thefront and back walls beingenlarged in steps above the discharge openingto provide a drive track with portions of at least two'different widths,

an elongated driver element slidably mounted within the drive track withdifferent fastener engaging portions movable in different width portionsof the drive track,

a magazine assembly coupled to the nosepiece structure for feedingsuccessive fasteners into the greatest width portion of the drive trackto be engaged by the corresponding fastener engaging portion of thefastener driving element,

and means for reciprocating the fastener driving element within thedrive track through a stroke substantially less than the length of thedrive track to cause a fastener supplied to the drive track to besuccessively engaged by different fastener engaging portions on thefastener driving element and successively moved through different widthportions of the drive track during successive strokes of the fastenerdriver element.

14. The fastener driving tool set forth in claim 13 including biasedretaining means in at least one of the different width portions of thedrive track for removably retaining a fastener in said portion of thedrive track between strokes of the fastener driving element.

15. The fastener driving tool set forth in claim 14 in which one wall ofthe drive track is at least partially defined by a wall structurecarrying a retaining means and detachably mounted on the other wall ofthe nosepiece structure.

16. The fastener driving tool set forth in claim 14 wherein the fastenerhas at least one elongated leg depending from a transverse portion andin which the retaining means includes a first means resiliently biasingthe fastener leg toward a wall of the nosepiece structure.

17. The fastener driving tool set forth in claim 16 in which theretaining means includes a second means resiliently biased to a positionoverlying the transverse portion of the fastener to permit movement ofthe fastener retained by the retaining means in only one directionthrough the drive track.

18. The fastener driving tool set forth in claim 17 in which the secondmeans includes spaced portions overlying spaced parts on the transverseportion of the fastener.

19. The fastener driving tool set forth in claim 17 in which I thesecond means includes means overlying a central part of the transverseportion of the fastener.

20. A tool for applying fasteners to workpieces comprising a nosepiecestructure defining a drive track with at least two different widthportions and terminating in a fastener discharge opening, the width ofsaid portions increasing considered upwardly from a lower end of thedrive track containing the discharge opening,

means for supplying fasteners adjacent an upper end of the drive track,

a fastener driver means having different width portions corresponding toand movable within the different width portions of the drive track,

fastener retaining means disposed in at least one of the different widthportions of the drive track for releasably retaining a fastener,

and means coupled to the fastener driver means for moving the fastenerdriver means through successive strokes in the drive track to move afastener through the drive track to the discharge opening in a series ofsuccessive strokes including more than one stroke, the fastener beingretained within the drive track by the fastener retaining means betweenat least one pair of successive strokes.

21. The fastener applying tool set forth in claim 20 in which thefastener retaining means includes at least two fastener retainingassemblies spaced along the drive track from each other and eachdisposed in a different width portion of the drive track.

22. A tool for applying to a workpiece staples having a crown portionand depending leg portions, said tool comprising: a drive trackstructure defining a drive track extending between a staple receivingopening through which staples are supplied to the drive track and astaple discharge opening from which staples are driven into theworkpiece; a staple drive member slidably movable in said drive track;power means for moving said staple drive member in said drive trackthrough a given drive stroke distance; the length of said drive trackbeing substantially an integral multiple of said drive stroke distance;spaced staple engaging portions on said staple drive member foradvancing staples successively through segments of said drive track,each such segment being substantially equal in length to said strokedistance; and a staple holding structure disposed along said drive trackbetween each adjacent pair of drive track segments; said holdingstructure including first holding means movable transverse to the drivetrack and engageable with the staple leg portions for capturing anadvanced staple in the drive track, and second holding means engageablewith the staple crown portion for preventing retrograde movement of anadvanced staple.

23. A tool as claimed in claim 22, further comprising a magazineassembly disposed adjacent said drive track structure for feedingstaples through said staple receiving opening.

24. A tool as claimed in claim 22 wherein the staples have a giventhickness and wherein the drive track segment adjacent the stapledischarge opening is substantially of said given thickness.

25. A tool as claimed in claim 24, said drive track segments decreasingin thickness from said staple receiving opening to said staple dischargeopening.

26. A tool as claimed in claim 25, said staple drive member includingdrive member segments extending between said staple engaging portions,each drive member segment being slidable in and substantially equal inthickness to a corresponding drive track segment.

27. A tool as claimed in claim 22, wherein said drive track structureincludes a wall defining one side of the drive track, and said first andsecond holding means are resiliently biased toward said wall.

28. A tool as claimed in claim 27, said second holding means comprisinga staple leg engaging member movable to clamp said staple leg portionsagainst said wall.

of N holding structures and N 1 drive track segments. =i

1. A tool for applying fasteners to a workpiece comprising a drive trackassembly defining a drive track with a fastener receiving opening and afastener discharge opening and having fastener storage meanstherebetween, a fastener driver slidable in the drive track and havingseparate portions for moving fasteners from the receiving openingthrough the storage means to the discharge opening in separate steps,and an operating means coupled to the fastener driver and operablethrough separate strokes during each of which one fastener is moved fromthe receiving opening to the storage means and another fastener is movedfrom the storage means through the discharge opening to be applied tothe workpiece, said drive track assembly including at least one enlargedportion in the drive track, and the fastener driver including acorresponding enlarged portion.
 2. A tool for applying fasteners to aworkpiece comprising a power actuated fastener driver movable through agiven stroke between normal and displaced positions, a drive trackstructure defining a drive track with a fastener receiving openingthrough which fasteners are supplied to the drive track and a fastenerdischarge opening through which fasteners are discharged from the drivetrack to the workpiece, the fastener receiving opening and the fastenerdischarge opening being spaced from each other along the drIve track adistance that is substantially an integral multiple of the given strokeand greater in value than one, said fastener driver being slidablymounted in the drive track, and spaced fastener engaging portions on thefastener driver for advancing successive fasteners through differentportions of the drive track on successive strokes of the fastenerdriver, the fastener having a given first width, and the drive trackhaving a first portion of said given first width adjacent the fastenerdischarge opening and a second portion between the first portion and thefastener receiving opening with a width greater than said given firstwidth.
 3. The tool set forth in claim 2 including retaining means in thedrive track for removably retaining fasteners in the drive track betweenstrokes of the fastener driver.
 4. A tool for applying fasteners of agiven first width to a workpiece comprising a power actuated fastenerdriver movable through a given stroke between normal and displacedpositions, a drive track structure defining a drive track with afastener receiving opening through which fasteners are supplied to thedrive track and a fastener discharge opening through which fasteners aredischarged from the drive track to the workpiece, the fastener receivingopening and the fastener discharge opening being spaced from each otheralong the drive track a distance that is substantially an integralmultiple of the given stroke and greater in value than one, saidfastener driver being slidably mounted in the drive track, spacedfastener engaging portions on the fastener driver for advancingsuccessive fasteners through different portions of the drive track onsuccessive strokes of the fastener driver, said drive track having afirst portion of said given first width adjacent the fastener dischargeopening and a second portion between the first portion and the fastenerreceiving opening with a width greater than said given first width, saidsecond portion of the drive track including portions of second and thirdwidths greater than the first width, and said fastener driver havingportions of first, second, and third widths slidably mounted in thefirst, second, and third width portions of the drive track.
 5. The toolset forth in claim 2 in which said second portion of the drive track hasa second width along its length, and the fastener driver has one portionof the first width slidably mounted in the first portion of the drivetrack and spaced portions of said second width slidably mounted in thesecond portion of the drive track.
 6. A tool for applying fasteners to aworkpiece comprising an elongated fastener driver operable through anoperating stroke between normal and actuated positions, said driverhaving a fastener driving portion at one end and at least one fastenerengaging transfer portion spaced above the fastener driving portion,drive track structure defining a drive track in which is slidablymounted the fastener driver, said drive track having a lower portionslidably receiving the fastener driving portion of the fastener driveand an enlarged storage portion disposed above the lower portion andslidably receiving the transfer portion of the fastener driver, fastenerretaining means carried on the drive track structure and disposed in theenlarged storage portion of the drive track for removably retaining afastener in the storage portion, fastener feeding means for feedingfasteners into the drive track, and operating means coupled to thefastener driver for actuating the fastener driver through successivestrokes during which the transfer portion of the fastener driver movesfasteners into the retaining means in the storage portion and thefastener driving portion of the fastener driver moves fasteners from thestorage portion into the workpiece.
 7. A tool for driving elongatedfasteners into a workpiece comprising a drive track structure defining adrive track and havIng a fastener receiving opening and a fastenerdischarge opening adapted to be placed adjacent the workpiece, fastenerdriving means including a fastener driver movably mounted in the drivetrack for movement through repeated strokes, a magazine assembly forsupplying a fastener through said receiving opening to the drive trackon each stroke of the fastener driver, and fastener storage means on thedrive track structure between the fastener receiving opening and thefastener discharge opening for storing a fastener between strokes of thefastener driver whereby more than one stroke of the fastener driver isnecessary to move a fastener from the fastener receiving opening to thefastener discharge opening, the fastener storage means including anumber of fastener storage assemblies spaced from each other along thedrive track, each assembly adapted to store a single fastener.
 8. Thetool set forth in claim 7 in which each fastener storage assemblyincludes deflectable means removably retaining a fastener in a positionin the drive track spaced between the fastener receiving opening and thefastener discharge opening.
 9. The tool set forth in claim 8 in whichthe deflectable means includes a rigid fastener engaging means andresilient biasing means acting on the rigid fastener engaging means. 10.The tool set forth in claim 8 in which the deflectable means includesflexible resilient means engaging the fastener.
 11. The tool set forthin claim 7 in which the fastener driver includes separate fastenerengaging portions for moving the fastener from a position adjacent thefastener receiving opening through the storage assemblies to thefastener discharge opening.
 12. A tool for driving fasteners into aworkpiece comprising a nosepiece structure defining a drive trackextending from a fastener receiving portion to a fastener dischargeopening with at least two drive track portions of different widthsbetween said receiving portion and said discharge opening, fastenerdriver means slidable in the drive track and having separate and spacedfastener engaging portions slidable in the different width portions ofthe drive track, fastener feeding means for feeding fasteners into thedrive track at the fastener receiving portion, and operating means formoving the fastener driver means through repeated strokes in the drivetrack to advance a fastener from the receiving station successivelythrough the different width portions of the drive track on successivestrokes of the fastener driver means whereby movement of the fastenerthrough the drive track from the receiving portion to the dischargeopening requires more than one stroke of the fastener driver means. 13.A fastener driving tool for driving fasteners into a workpiececomprising a nosepiece structure including spaced front and back wallsjoined by side walls defining a drive track, a lower end of the drivetrack terminating in a discharge opening and the spacing between thefront and back walls being enlarged in steps above the discharge openingto provide a drive track with portions of at least two different widths,an elongated driver element slidably mounted within the drive track withdifferent fastener engaging portions movable in different width portionsof the drive track, a magazine assembly coupled to the nosepiecestructure for feeding successive fasteners into the greatest widthportion of the drive track to be engaged by the corresponding fastenerengaging portion of the fastener driving element, and means forreciprocating the fastener driving element within the drive trackthrough a stroke substantially less than the length of the drive trackto cause a fastener supplied to the drive track to be successivelyengaged by different fastener engaging portions on the fastener drivingelement and successively moved through different width portions of thedrive track during successive strokes of the fastener driver eLement.14. The fastener driving tool set forth in claim 13 including biasedretaining means in at least one of the different width portions of thedrive track for removably retaining a fastener in said portion of thedrive track between strokes of the fastener driving element.
 15. Thefastener driving tool set forth in claim 14 in which one wall of thedrive track is at least partially defined by a wall structure carrying aretaining means and detachably mounted on the other wall of thenosepiece structure.
 16. The fastener driving tool set forth in claim 14wherein the fastener has at least one elongated leg depending from atransverse portion and in which the retaining means includes a firstmeans resiliently biasing the fastener leg toward a wall of thenosepiece structure.
 17. The fastener driving tool set forth in claim 16in which the retaining means includes a second means resiliently biasedto a position overlying the transverse portion of the fastener to permitmovement of the fastener retained by the retaining means in only onedirection through the drive track.
 18. The fastener driving tool setforth in claim 17 in which the second means includes spaced portionsoverlying spaced parts on the transverse portion of the fastener. 19.The fastener driving tool set forth in claim 17 in which the secondmeans includes means overlying a central part of the transverse portionof the fastener.
 20. A tool for applying fasteners to workpiecescomprising a nosepiece structure defining a drive track with at leasttwo different width portions and terminating in a fastener dischargeopening, the width of said portions increasing considered upwardly froma lower end of the drive track containing the discharge opening, meansfor supplying fasteners adjacent an upper end of the drive track, afastener driver means having different width portions corresponding toand movable within the different width portions of the drive track,fastener retaining means disposed in at least one of the different widthportions of the drive track for releasably retaining a fastener, andmeans coupled to the fastener driver means for moving the fastenerdriver means through successive strokes in the drive track to move afastener through the drive track to the discharge opening in a series ofsuccessive strokes including more than one stroke, the fastener beingretained within the drive track by the fastener retaining means betweenat least one pair of successive strokes.
 21. The fastener applying toolset forth in claim 20 in which the fastener retaining means includes atleast two fastener retaining assemblies spaced along the drive trackfrom each other and each disposed in a different width portion of thedrive track.
 22. A tool for applying to a workpiece staples having acrown portion and depending leg portions, said tool comprising: a drivetrack structure defining a drive track extending between a staplereceiving opening through which staples are supplied to the drive trackand a staple discharge opening from which staples are driven into theworkpiece; a staple drive member slidably movable in said drive track;power means for moving said staple drive member in said drive trackthrough a given drive stroke distance; the length of said drive trackbeing substantially an integral multiple of said drive stroke distance;spaced staple engaging portions on said staple drive member foradvancing staples successively through segments of said drive track,each such segment being substantially equal in length to said strokedistance; and a staple holding structure disposed along said drive trackbetween each adjacent pair of drive track segments; said holdingstructure including first holding means movable transverse to the drivetrack and engageable with the staple leg portions for capturing anadvanced staple in the drive track, and second holding means engageablewith the staple crown portion for preventing retRograde movement of anadvanced staple.
 23. A tool as claimed in claim 22, further comprising amagazine assembly disposed adjacent said drive track structure forfeeding staples through said staple receiving opening.
 24. A tool asclaimed in claim 22 wherein the staples have a given thickness andwherein the drive track segment adjacent the staple discharge opening issubstantially of said given thickness.
 25. A tool as claimed in claim24, said drive track segments decreasing in thickness from said staplereceiving opening to said staple discharge opening.
 26. A tool asclaimed in claim 25, said staple drive member including drive membersegments extending between said staple engaging portions, each drivemember segment being slidable in and substantially equal in thickness toa corresponding drive track segment.
 27. A tool as claimed in claim 22,wherein said drive track structure includes a wall defining one side ofthe drive track, and said first and second holding means are resilientlybiased toward said wall.
 28. A tool as claimed in claim 27, said secondholding means comprising a staple leg engaging member movable to clampsaid staple leg portions against said wall.
 29. A tool as claimed inclaim 27 wherein each said first and second holding means includes arigid element and a spring biasing said rigid element toward said wall,and each rigid element including a cam surface engageable by a staple insaid drive track for retracting said rigid element.
 30. A tool asclaimed in claim 22 including a single holding structure and two drivetrack segments.
 31. A tool as claimed in claim 22 including a pluralityof N holding structures and N + 1 drive track segments.